Hyaluronic acid. Glycolic acid. Salicylic acid. L-ascorbic acid. Poly hydroxy acid. Sometimes, choosing skincare products can make you feel like you’re back in chemistry class—you’re not entirely sure what each acid in your skincare does and you’re scared it might burn your face. Which is why we’re here to tell you exactly how each one of these ingredients can work for your skin and how to incorporate it into your skincare routine without burning your face.